Hi! I’m a newbie to this forum and to home renovation in general. I am preparing to put in hardwood floors on my second floor, but first needed to replace some subfloor due to a heaving in the boards. When the contractor pulled up the subfloor (it’s the original subfloor when house was built in 1992), they discovered it was tongue-and-groove subflooring along the edges (see photo). The joists are spaced 24” OC and the subfloor is 3/4” thick. My question is this: The contractor said he will replace it with non tongue & groove 3/4” subfloor, but I am concerned that the tongue & groove is needed to support the subloorband keep it from flexing when I step on it. What are my options to brace this area? Blocking? Or...? If blocking, how do you do that on a truss design like this? Im worried the contractor is going to try to take the easy way out on this and just toss down the plywood. https://imgur.com/42HvWos

Sorry. I had to put the picture as a link. Couldn’t get the image to appear in the message itself.

I would use 1/2 inchX 8" wide strips glued and screwed along the edges where the T&G is lost, 4 " on each side of where the T&G used to be. It would be easy to get the first edge prepped, then glue and screw through pre-drilled holes in the 3/4 inch square edge patch sheets that will hold everything so the glue can cure.